Method and apparatus for initialization and operation of field-commutated motors and machines incorporating field-commutated motors

A method of operating an apparatus including a field-commutated motor comprising the steps of:

• initializing the motor, the step of initializing including the steps of:
• applying a first voltage of a first orientation and of a first magnitude to one of the rotor and the stator;
• determining a first rotor angle corresponding to application of the first voltage;
• applying a second voltage to one of the rotor and the stator, the second voltage having an orientation substantially equal to the first orientation and of second magnitude different from the first magnitude, the second voltage being applied when the motor is under a load substantially equal to the load applied during the application of the first voltage;
• determining a second rotor angle corresponding to the application of the second voltage;
• determining an error angle, as a function of at least the first and second rotor angles, for allowing initialization of the motor;
• determining a third rotor angle;
• determining an initialized rotor angle from the third rotor angle and the error angle;
• and
• using the initialized angle in providing power to the motor for rotating the motor for operating the apparatus.

Apparatus for initializing a field-commutated motor having a rotor and a stator, comprising:

• a motor power supply for providing power to at least one of the rotor and stator of the motor;
• a sensor for determining rotor angle;
• a processor in electrical communication with said sensor and said power supply, said processor including;
• means for applying a first voltage of a first orientation and of a first magnitude to one of the rotor and the stator;
• means, responsive to said sensor, for determining a first rotor angle corresponding to application of the first voltage;
• means for applying a second voltage to one of the rotor and the stator, the second voltage having an orientation substantially equal to the first orientation and of second magnitude different from the first magnitude;
• means for determining a second rotor angle corresponding to the application of the second voltage;
• and
• means for determining an error angle for allowing initialization of the motor, said means determining the error angle of a function of at least the following:
• the first and second rotor angles;
• one of the first voltage and the current corresponding thereto;
• and one of the second voltage and the current corresponding thereto.

Field-commutated motor apparatus, comprising:

• a field-commutated motor having a rotor and a stator;
• a motor power supply for providing power to at least one of the rotor and stator of the motor;
• a sensor for determining rotor angles;
• a processor in electrical communication with said sensor and said power supply, said processor including;
• means for applying a first voltage of a first orientation and of a first magnitude to one of the rotor and the stator;
• means, responsive to said sensor, for determining a first rotor angle corresponding to application of the first voltage;
• means for applying a second voltage to one of the rotor and the stator, the second voltage having an orientation substantially equal to the first orientation and of second magnitude different from the first magnitude;
• means for determining a second rotor angle corresponding to the application of the second voltage;
• means for determining an error angle for allowing initialization of the motor, said means determining the error angle of a function of at least the following:
• the first and second rotor angles;
• one of the first voltage and the current corresponding thereto;
• and one of the second voltage and the current corresponding thereto;
• and
• means for determining an initialized rotor angle from a third rotor angle and the error angle, such that said power supply can provide power to said at least one of the stator and the rotor for initiating the rotor.